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• 1. [Article] Thermoelectric properties of quantum dots and other low-dimensional systems

  xii, 106 p. : ill. (some col.)

  Citation × Citation Citation Abstract Copy Title: Thermoelectric properties of quantum dots and other low-dimensional systems Author: Nakpathomkun, Natthapon, 1973- Year: 2011, 2010 xii, 106 p. : ill. (some col.) Title: Thermoelectric properties of quantum dots and other low-dimensional systems Author: Nakpathomkun, Natthapon, 1973- Year: 2011, 2010 xii, 106 p. : ill. (some col.) Close

• 2. [Article] The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires

  xi, 193 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.

  Citation × Citation Citation Abstract Copy Title: The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires Author: Hoffmann, Eric A., 1982- Year: 2010, 2009 xi, 193 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. Title: The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires Author: Hoffmann, Eric A., 1982- Year: 2010, 2009 xi, 193 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. Close

• 3. [Article] CdS Quantum Dot-Sensitized Solar Cells Based on Nano-Branched TiO2 Arrays

  Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored ...

  Citation × Citation Citation Abstract Copy Title: CdS Quantum Dot-Sensitized Solar Cells Based on Nano-Branched TiO2 Arrays Author: Liu, Chang, Li, Yitan, Wei, Lin, Wu, Cuncun, Chen, Yanxue, Mei, Liangmo, Jiao, Jun Year: 2014 Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored by controlling the growth time, after which CdS quantum dots were deposited on the nano-branched TiO2 arrays using the successive ionic layer adsorption and reaction method to make a photoanode for quantum dot-sensitized solar cells (QDSCs). The photovoltaic properties of the CdS-sensitized nano-branched TiO2 solar cells were studied systematically. A short-circuit current intensity of approximately 7 mA/cm2 and a light-to-electricity conversion efficiency of 0.95% were recorded for cells based on optimized nano-branched TiO2 arrays, indicating an increase of 138% compared to those based on unbranched TiO2 nanorod arrays. The improved performance is attributed to a markedly enlarged surface area provided by the nanobranches and better electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunks Title: CdS Quantum Dot-Sensitized Solar Cells Based on Nano-Branched TiO2 Arrays Author: Liu, Chang, Li, Yitan, Wei, Lin, Wu, Cuncun, Chen, Yanxue, Mei, Liangmo, Jiao, Jun Year: 2014 Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored by controlling the growth time, after which CdS quantum dots were deposited on the nano-branched TiO2 arrays using the successive ionic layer adsorption and reaction method to make a photoanode for quantum dot-sensitized solar cells (QDSCs). The photovoltaic properties of the CdS-sensitized nano-branched TiO2 solar cells were studied systematically. A short-circuit current intensity of approximately 7 mA/cm2 and a light-to-electricity conversion efficiency of 0.95% were recorded for cells based on optimized nano-branched TiO2 arrays, indicating an increase of 138% compared to those based on unbranched TiO2 nanorod arrays. The improved performance is attributed to a markedly enlarged surface area provided by the nanobranches and better electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunks Close

• 4. [Article] Thin Film Solar Cells Using ZnO Nanowires, Organic Semiconductors and Quantum Dots

  A thin film organic/ inorganic hybrid solar cell was fabricated by incorporating ZnO nanowires, n- and p-type organic semiconductors and inorganic quantum dots. The basic cell design involved the electrodeposition ...

  Citation × Citation Citation Abstract Copy Title: Thin Film Solar Cells Using ZnO Nanowires, Organic Semiconductors and Quantum Dots Author: VanSant, Kaitlyn Year: 2007 A thin film organic/ inorganic hybrid solar cell was fabricated by incorporating ZnO nanowires, n- and p-type organic semiconductors and inorganic quantum dots. The basic cell design involved the electrodeposition of ZnO nanowires grown on a substrate coated with a transparent conductive oxide. The ZnO nanowires were coated with a thin layer of an organic n-type material, followed by a deposition of inorganic quantum dots. A p-type polymer layer was subsequently deposited and the sample was then contacted with gold to form a quantum dot layer sandwiched between a p-n junction of organic conductive materials. Various materials and processing methods were adjusted, using I-V characteristics, photovoltage and/ or photocurrent measurements to determine the performance of the cell. Each constituent material in the basic device design was evaluated in terms of its contribution to the sample characteristics. A variety of deposition techniques were investigated to obtain homogeneous layers. Different annealing procedures were explored with the intent of balancing the time and temperatures required for electrical activation with material constraints such as tendency towards oxidation and low melting points. The effect of time on the sample characteristics was also observed. The evaluation primarily includes data for samples that led to design modifications aimed at improving both electrical properties and quantum efficiencies. This research led to the development of a hybrid solar cell sensitized by the addition of quantum dots. The organic semiconductors were used to form a p-n junction, and the p-type polymer also served as an active absorber layer. The quantum dots were used as the inorganic absorber fayer, and the results show that the range of optical absorption in the cell can be modified by adjusting particle size. In addition, the ZnO nanowires appear to improve charge transfer, when used with materials that have favorable band offsets. Title: Thin Film Solar Cells Using ZnO Nanowires, Organic Semiconductors and Quantum Dots Author: VanSant, Kaitlyn Year: 2007 A thin film organic/ inorganic hybrid solar cell was fabricated by incorporating ZnO nanowires, n- and p-type organic semiconductors and inorganic quantum dots. The basic cell design involved the electrodeposition of ZnO nanowires grown on a substrate coated with a transparent conductive oxide. The ZnO nanowires were coated with a thin layer of an organic n-type material, followed by a deposition of inorganic quantum dots. A p-type polymer layer was subsequently deposited and the sample was then contacted with gold to form a quantum dot layer sandwiched between a p-n junction of organic conductive materials. Various materials and processing methods were adjusted, using I-V characteristics, photovoltage and/ or photocurrent measurements to determine the performance of the cell. Each constituent material in the basic device design was evaluated in terms of its contribution to the sample characteristics. A variety of deposition techniques were investigated to obtain homogeneous layers. Different annealing procedures were explored with the intent of balancing the time and temperatures required for electrical activation with material constraints such as tendency towards oxidation and low melting points. The effect of time on the sample characteristics was also observed. The evaluation primarily includes data for samples that led to design modifications aimed at improving both electrical properties and quantum efficiencies. This research led to the development of a hybrid solar cell sensitized by the addition of quantum dots. The organic semiconductors were used to form a p-n junction, and the p-type polymer also served as an active absorber layer. The quantum dots were used as the inorganic absorber fayer, and the results show that the range of optical absorption in the cell can be modified by adjusting particle size. In addition, the ZnO nanowires appear to improve charge transfer, when used with materials that have favorable band offsets. Close

• 5. [Article] Transport in silicon metal oxide semiconductor quantum dots

  Herein, a program of research is detailed related to transport through the Si metal oxide semiconductor (MOS) quantum dots fabricated in a process flow compatible with modern ULSI (ultra large scale integrated ...

  Citation × Citation Citation Abstract Copy Title: Transport in silicon metal oxide semiconductor quantum dots Author: Gunther, Allen David Herein, a program of research is detailed related to transport through the Si metal oxide semiconductor (MOS) quantum dots fabricated in a process flow compatible with modern ULSI (ultra large scale integrated circuit). Silicon quantum dots were fabricated by placing split gates within a MOSFET structure. Quantum dots of several sizes and geometries were fabricated by this process for the purpose of investigating the effects of size and shape on quantized transport through the dots. The transport properties of the different quantum dot sizes and shapes were investigated at low temperatures, and compared to normal MOSFETs fabricated by the same technology. Equilibrium measurements with the device biased in the regime from the onset of weak inversion to just past the onset of strong inversion revealed strongly oscillatory behavior in the tunneling conductance. The conductance peaks appear to map an energy level spectrum in the dot as the inversion and depletion gates are separately swept. Symmetric devices, biased both symmetrically and asymmetrically, show two groups of "branches" which evolve with different slopes in the V[subscript Inv]-V[subscript Depl] plane. An asymmetric device studied shows three groups of branches. In addition, a fine structure is observed in the conductance peak behavior of two devices. This apparent energy level structure is compared to the body of literature on the so-called artificial atoms, as well as self-consistent three dimensional quantum mechanical solutions for the energy levels in the same dot structure, which qualitatively agree with the overall slope of the observed data. However, the calculations reveal only the multiple sets of slopes when asymmetrically biased. These multiple slopes are postulated to arise due to the splitting of the degenerate states of the symmetric structure as the bias makes the structure increasingly asymmetric. Finally, a simplified model is presented which shows how slight asymmetry in the dot confining potential can give rise to both a fine structure and multiple slopes in the branches, and several alternative mechanisms are presented to explain the origin of the fine structure observed. Title: Transport in silicon metal oxide semiconductor quantum dots Author: Gunther, Allen David Herein, a program of research is detailed related to transport through the Si metal oxide semiconductor (MOS) quantum dots fabricated in a process flow compatible with modern ULSI (ultra large scale integrated circuit). Silicon quantum dots were fabricated by placing split gates within a MOSFET structure. Quantum dots of several sizes and geometries were fabricated by this process for the purpose of investigating the effects of size and shape on quantized transport through the dots. The transport properties of the different quantum dot sizes and shapes were investigated at low temperatures, and compared to normal MOSFETs fabricated by the same technology. Equilibrium measurements with the device biased in the regime from the onset of weak inversion to just past the onset of strong inversion revealed strongly oscillatory behavior in the tunneling conductance. The conductance peaks appear to map an energy level spectrum in the dot as the inversion and depletion gates are separately swept. Symmetric devices, biased both symmetrically and asymmetrically, show two groups of "branches" which evolve with different slopes in the V[subscript Inv]-V[subscript Depl] plane. An asymmetric device studied shows three groups of branches. In addition, a fine structure is observed in the conductance peak behavior of two devices. This apparent energy level structure is compared to the body of literature on the so-called artificial atoms, as well as self-consistent three dimensional quantum mechanical solutions for the energy levels in the same dot structure, which qualitatively agree with the overall slope of the observed data. However, the calculations reveal only the multiple sets of slopes when asymmetrically biased. These multiple slopes are postulated to arise due to the splitting of the degenerate states of the symmetric structure as the bias makes the structure increasingly asymmetric. Finally, a simplified model is presented which shows how slight asymmetry in the dot confining potential can give rise to both a fine structure and multiple slopes in the branches, and several alternative mechanisms are presented to explain the origin of the fine structure observed. Close